HISTOCHEMICAL AND CONFOCAL LASER-SCANNING MICROSCOPY STUDY OF THE BONE TITANIUM INTERFACE - AN EXPERIMENTAL-STUDY IN RABBITS

The aim of our study was an analysis of the presence of an unmineraliz ed bone matrix between mineralized bone and titanium screws in rabbit tibiae. A microscopical analysis, using a histochemical technique, was performed on the titanium-bone interface of commercially pure titaniu m implants placed in rabbit tibiae and harvested after 2 months. Thin ground sections of the specimens were prepared by the cutting-grinding system and stained using the von Kossa method for calcium salts and b asic fuchsin for osteoid. The microscopical and morphometrical evaluat ion showed that bone covered about 40% (+/-7.5%) of all implants. Mine ralized bone was, however, in direct contact with the titanium surface on only about 10% of the implant, while in the remaining 30% the mine ralized bone was separated from the implant by an unmineralized tissue . This basophilic, probably osteoid matrix, could represent the medium that allows the biochemical exchanges between bone and cells under th e influence of the implant. A small, optically translucent gap (1-5 mu m), probably an artifact, was present in some areas between titanium and bone. Confocal laser scanning microscopy (CLSM) in a fluorescent m ode showed the presence at the interface of a fluorescent material. Re sults from our study showed that light microscopy of thin ground secti ons allowed a good analysis of the real nature of the titanium-bone in terface. Moreover, this double staining technique showed the presence of an unmineralized bone matrix at most of the bone-titanium interface .